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Performance of A1C for the classification and prediction of diabetes.

TitlePerformance of A1C for the classification and prediction of diabetes.
Publication TypeJournal Article
Year of Publication2011
AuthorsSelvin E, Steffes MW, Gregg E, Brancati FL, Coresh J
JournalDiabetes Care
Volume34
Issue1
Pagination84-9
Date Published2011 Jan
ISSN1935-5548
KeywordsBlood Glucose, Diabetes Mellitus, Fasting, Female, Glycated Hemoglobin A, Humans, Male, Middle Aged
Abstract

OBJECTIVE: Although A1C is now recommended to diagnose diabetes, its test performance for diagnosis and prognosis is uncertain. Our objective was to assess the test performance of A1C against single and repeat glucose measurements for diagnosis of prevalent diabetes and for prediction of incident diabetes.

RESEARCH DESIGN AND METHODS: We conducted population-based analyses of 12,485 participants in the Atherosclerosis Risk in Communities (ARIC) study and a subpopulation of 691 participants in the Third National Health and Nutrition Examination Survey (NHANES III) with repeat test results.

RESULTS: Against a single fasting glucose ≥126 mg/dl, the sensitivity and specificity of A1C ≥6.5% for detection of prevalent diabetes were 47 and 98%, respectively (area under the curve 0.892). Against repeated fasting glucose (3 years apart) ≥126 mg/dl, sensitivity improved to 67% and specificity remained high (97%) (AUC 0.936). Similar results were obtained in NHANES III against repeated fasting glucose 2 weeks apart. The accuracy of A1C was consistent across age, BMI, and race groups. For individuals with fasting glucose ≥126 mg/dl and A1C ≥6.5% at baseline, the 10-year risk of diagnosed diabetes was 88% compared with 55% among those individuals with fasting glucose ≥126 mg/dl and A1C 5.7-

CONCLUSIONS: A1C performs well as a diagnostic tool when diabetes definitions that most closely resemble those used in clinical practice are used as the "gold standard." The high risk of diabetes among individuals with both elevated fasting glucose and A1C suggests a dual role for fasting glucose and A1C for prediction of diabetes.

DOI10.2337/dc10-1235
Alternate JournalDiabetes Care
PubMed ID20855549
PubMed Central IDPMC3005486
Grant ListN01HC55020 / HL / NHLBI NIH HHS / United States
K01-DK-076595 / DK / NIDDK NIH HHS / United States
N01HC55018 / HL / NHLBI NIH HHS / United States
N01-HC-55022 / HC / NHLBI NIH HHS / United States
P60-DK-079637 / DK / NIDDK NIH HHS / United States
N01-HC-55016 / HC / NHLBI NIH HHS / United States
P30 DK079637 / DK / NIDDK NIH HHS / United States
N01HC55022 / HL / NHLBI NIH HHS / United States
N01-HC-55021 / HC / NHLBI NIH HHS / United States
N01HC55015 / HL / NHLBI NIH HHS / United States
R21-DK-080294 / DK / NIDDK NIH HHS / United States
K01 DK076595 / DK / NIDDK NIH HHS / United States
N01-HC-55019 / HC / NHLBI NIH HHS / United States
N01-HC-55015 / HC / NHLBI NIH HHS / United States
P60 DK079637 / DK / NIDDK NIH HHS / United States
N01-HC-55020 / HC / NHLBI NIH HHS / United States
K24-DK-62222 / DK / NIDDK NIH HHS / United States
N01HC55016 / HL / NHLBI NIH HHS / United States
N01HC55019 / HL / NHLBI NIH HHS / United States
R21 DK080294 / DK / NIDDK NIH HHS / United States
N01-HC-55018 / HC / NHLBI NIH HHS / United States
N01HC55021 / HL / NHLBI NIH HHS / United States
K24 DK062222 / DK / NIDDK NIH HHS / United States